Medication is often dispensed using a unit dose medical cartridge, such as an ampoule, vial, or syringe, and a syringe holder, injector, or adapter. The cartridge typically has a barrel with a needle at one end and a plunger at the other end. Such cartridges are often referred to as “pre-filled syringes” because they contain a specific dosage or volume of medication when they are initially provided, as compared to conventional syringes, which are furnished empty and filled by the user prior to use. Alternatively, the medical cartridge may include a rubber stopper instead of a needle, and/or a piston rather than a plunger.
Because of the threat of communicable diseases, a number of syringes and adapters have been developed to prevent accidental needle sticks or inadvertent reuse of needle devices. Many of these, however, are not easy to use or are complicated to manufacture, resulting in less effective disposable syringe devices. For example, U.S. Pat. No. 5,569,211 discloses a syringe that allows the needle of the syringe to be withdrawn into the barrel of the syringe after medication is dispensed from it. This device, however, is a specially designed substitute for a conventional syringe, and cannot be used to hold commercially available pre-filled syringes.
U.S. Pat. No. 5,522,812 discloses a syringe shield device for holding a conventional cartridge not having its own needle. The device includes a cylindrical body, a double needle assembly, a cylindrical shield, a special collar piece allowing the shield to be drawn over the needle and locked, and a plunger assembly, resulting in a device that is potentially difficult and expensive to manufacture. The device also requires two hands to operate, one to hold the body, and one to rotate the shield into the locked position, which may be inconvenient to the medical professional using the device.
Another consideration with unit dose cartridges and pre-filled syringes is that they are often made from glass, particularly for holding certain vaccines or biotech drugs where concern about micro-organisms or other contaminants is most critical. Glass cartridges and pre-filled syringes are very fragile and often break during transportation or use. Some existing adapters may not adequately protect the syringe contained therein from such risks. Others provide greater protection for the cartridge, but may obstruct viewing the syringe when the device is being used, hampering monitoring the medication being delivered.
Accordingly, adapters or guards for receiving syringes or other medical cartridges would be considered useful.